The present disclosure relates to an electrostatic latent image developing toner and an image forming apparatus.
In electrophotography, a surface of an electrophotographic photosensitive member (also referred to below simply as a photosensitive member) serving as an image bearing member is charged, and subsequently the photosensitive member is exposed to light, thereby forming an electrostatic latent image on the photosensitive member. Next, the electrostatic latent image is developed into a toner image using a developer, and the toner image is transferred to a recording medium. The toner image on the recording medium is then fixed using a fixing device including a pressing roller, for example, to form an image on the recording medium.
Ozone may be generated when a photosensitive member is charged in an image formation process by electrophotography. Such ozone may react with nitrogen in the air to form a nitrogen oxide (NOx), and the nitrogen oxide may react with moisture in the air to form a product (also referred to below as a charging product) such as nitric acid. The charging product may adhere to a surface of the photosensitive member. In such a situation, the photosensitive member decreases in surface electric resistance to disrupt latent-image charge on the photosensitive member. In a situation in which image formation is performed with such a photosensitive member in a high-humidity environment, image deletion (a phenomenon described as blurring of an image that looks as if the image was smeared) may occur. In particular, image deletion tends to easily occur in the case of a photosensitive member that includes an amorphous silicon-containing photosensitive layer in a surface portion thereof, because a surface of the photosensitive layer is relatively highly hydrophilic, and thus a charging product easily adheres to the surface of the photosensitive layer.
In order to cope with the image deletion, it has been contemplated to include titanium oxide particles having abrasive action as an external additive in an electrostatic latent image developing toner (also referred to below simply as a toner). A known technique for example inhibits occurrence of image deletion by causing titanium oxide particles added as an external additive to scratch off a charging product adhering to a surface of a photosensitive member.